Jae-Jeong Lee

Korea University, Sŏul, Seoul, South Korea

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Publications (8)22.59 Total impact

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    ABSTRACT: The previous study demonstrated that the streptozotocin (STZ)-induced diabetic mice can be cured by injecting the regenerating pancreatic extract (RPE) of the partially pancreatectomized Wistar-Kyoto rats. In this study, to characterize the complex pattern of protein expression in RPE, the proteins of altered expression level after the pancreatectomy were identified by 2-dimensional electrophoresis (2-DE) and mass spectrometry. Of 76 significantly up- or down-regulated protein spots, 61 were identified by MALDI-TOF/MS. Moreover, the whole RPE was fractionated into 4 groups using an anion-exchange chromatography and each fraction's cell proliferating activity was measured by MTT assay. Compared to the normal pancreatic extract, fraction 3 and 4 of RPE showed the maximal cell proliferating activity. On 2-DE of 3 and 4 fractions, a total of 10 spots, which are differentially expressed after the pancreatectomy, were identified by MS/MS. Of these identified proteins, Reg III which might be functionally associated with well known regenerating factor (Reg I) was found. Taken together, our results demonstrated that the differential protein expression associated with pancreas regeneration could be sought by 2-DE and mass spectroscopy and suggested that the pre-fractionation method combined with in vitro cell proliferation assay is effectively used to pinpoint the active components for pancreas regeneration.
    Biochimica et Biophysica Acta 06/2005; 1749(1):23-32. · 4.66 Impact Factor
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    ABSTRACT: Recent reports have suggested that mesenchymal cells derived from bone marrow may differentiate into not only mesenchymal lineage cells but also other lineage cells. There is possibility for insulin-producing cells (IPCs) to be differentiated from mesenchymal cells. We used self-functional repair stimuli of stem cells by partial injury. Rat pancreatic extract (RPE) from the regenerating pancreas (2 days after 60% pancreatectomy) was treated to rat mesenchymal cells. After the treatment of RPE, they made clusters like islet of Langerhans within a week and expressed four pancreatic endocrine hormones; insulin, glucagon, pancreatic polypeptide, and somatostatin. Moreover, IPCs released insulin in response to normal glucose challenge. Here we demonstrate that the treatment of RPE can differentiate rat mesenchymal cells into IPCs which can be a potential source for the therapy of diabetes.
    Biochemical and Biophysical Research Communications 06/2005; 330(4):1299-305. · 2.28 Impact Factor
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    ABSTRACT: Pulmonary delivery provides the most promising non-parenteral route of insulin administration. Insulin was used as a model protein to demonstrate the feasibility of using protein crystals for the pulmonary delivery of a sustained-release protein drug formulation. Insulin microcrystals with a mean diameter of 3 microm were prepared using a seed zone method. The yield of crystallization was very high (95.8 +/- 0.97%), and the microcrystals were recovered with high efficiency (>98%) by centrifugation. Morphological examination using scanning electron microphotography showed the microcrystals to be of a homogeneous rhombohedral shape, with some rhombus forms, without aggregates. After the administration of 32 U/kg of the microcrystal suspension to STZ-induced diabetic SD rats by intratracheal instillation, the blood glucose levels were reduced and hypoglycemia was prolonged over 13 h, as compared to the insulin solution. The percent minimum reductions of the blood glucose concentration (% MRBG) produced by the microcrystal suspension and insulin solution reached 36.5 and 37.2%, respectively, of the initial level, and the percent total reductions in blood glucose (% TRBG(13 h)) were 34.4 and 25.0%, respectively. In the case of inhalation using a sieve-type ultrasonic nebulizer, the % MRBG produced by the microcrystal suspension and insulin solution were 21.7 and 26.3%, respectively, of the initial level, and the % TRBG(13 h) were 66.7 and 58.4%, respectively. However, the hypoglycemic effects of the microcrystal suspension were prolonged over 7 h, which compares favorably with the insulin solution (P<0.5 by unpaired t-test). These results could be attributed to the sustained-release of insulin from the microcrystals, which were deposited widely throughout the entire lung.
    European Journal of Pharmaceutical Sciences 07/2004; 22(2-3):107-16. · 2.99 Impact Factor
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    ABSTRACT: Recent epidemiological studies suggest that alcohol consumption is one of the risk factors leading to type 2 diabetes, but the direct effect of ethanol on beta-cell gene expression is not known. Here, using cDNA RDA method, we isolated 43 ethanol-induced genes in pancreatic beta-cells, and confirmed their differential expression by Northern blot or semi-quantitative RT-PCR. These genes were further categorized by the functional criteria based on the published data; Translation, Transcription, Metabolism, Signal transduction, Transport, Structure, Cytoskeleton, Regulation, or Putative/Unknown genes. The effects of each gene on beta-cell function need to be further investigated, however, the present data strongly suggest that these genes might be related to the metabolic alterations caused by ethanol as indicated in earlier study. In particular, RPS3 gene expression was increased by ethanol, glucosamine, and cytokines, implying that ethanol might decrease the metabolic activity by oxidative stress in beta-cells. Therefore, cloning of these genes in full-length and the detailed studies of each gene on beta-cell functions might provide clues on the pathophysiology of type 2 diabetes caused by alcohol.
    Experimental and Molecular Medicine 03/2004; 36(1):36-42. · 2.57 Impact Factor
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    ABSTRACT: Morphological and functional changes of rat pancreatic islets caused by administration of streptozotocin (STZ) and the bioavailability of insulin formulations administered to STZ-induced diabetic rats with fasting (12 h) or non-fasting were investigated. Islets isolated from normal rats maintained a good three-dimensional structure and the islet yield was 962.5+/-86.5 islet equivalent number (IEQ, islets converted to an average diameter of 150 microm). In the diabetic group (>500 mg/ml blood glucose), the islet yield was only 44.4+/-8.3 IEQ and the islet was severely damaged. The minimum reduction of blood glucose of each formulation, such as insulin solution, microcrystal, and insulin microcrystal capsule, was shown to be 11.3, 11.0, and 16.3 mg/dl, respectively, at 6 h in fasting with diabetic rats. These results indicated that the administration of insulin formulations to the fasting groups increased the severe hypoglycemic effect of insulin action more than in non-fasting diabetic rats. The diabetic rat with fasting has a regulatory disorder in maintaining the blood glucose level. Accordingly, the validity of pharmacological availability as an optimal modeling of insulin formulations is best in non-fasting STZ-induced diabetic rats.
    Bioscience Biotechnology and Biochemistry 11/2003; 67(11):2396-401. · 1.27 Impact Factor
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    ABSTRACT: In this study, the effects of rat pancreatic extract (RPE) on regeneration of impaired mouse pancreas and proliferation of beta-cell line (HIT-T15) were investigated. RPE from the regenerating pancreas (2 days after 60% pancreatectomy) was treated to cure streptozotocin (STZ) induced diabetes in BALB/c mice. RPE-treated BALB/c mice for 21 consecutive days became euglycemic by day 30 and remained normoglycemic during a 150 day follow-up. Saline treated mice remained hyperglycemic sustained uncontrolled hyperglycemia. Islet neogenesis was observed in RPE-treated mice and confirmed by use of immunocytochemistry. Morphometric analysis of pancreas in reverted RPE-treated mice showed a new population of small islets compared with saline controls and an increased islet number. When HIT-T15 cells were treated with RPE, HIT-T15 cell proliferation and insulin secretion increased with increases in the RPE concentration. These results imply that RPE have the regeneration factors and help in the cure of diabetes.
    Biochemical and Biophysical Research Communications 10/2003; 309(3):528-32. · 2.28 Impact Factor
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    ABSTRACT: This study developed a microcrystallization process for indomethacin, a nonsteroidal anti-inflammatory drug (NSAID), using a pH-shift method in aqueous solution. The physicochemical properties of the microcrystals produced were similar to those of the standard crystalline powder in X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR) analyses, except for a lower XRD peak height and a slightly lower melting temperature (Tm) (1.5 degrees C). Phase contrast microscopy and scanning electron microscopy (SEM) showed that the indomethacin microcrystals were plate-like with a uniform size distribution (mean diameter =10.4+/-0.4 microm). In the initial phase, the dissolution rate of the indomethacin microcrystals was about 2.2 times higher than that of the standard crystalline powder. The biological activity of the indomethacin microcrystals was about 20% higher than that of the standard crystalline powder in their ability to inhibit the proliferation of colon cancer cells (HT-29).
    International Journal of Pharmaceutics 10/2003; 263(1-2):141-50. · 3.99 Impact Factor
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    ABSTRACT: Various epidemiological studies suggest that alcohol intake is one of the risk factors leading to type II or non-insulin-dependent diabetes mellitus (NIDDM), but the effect of alcohol on beta-cell function remains unexplored. To study the mechanism of the diabetogenic action of ethanol, we investigated the effect of ethanol on beta-cell functions using a single clonal beta-cell line, HIT-T15 cells. When HIT cells were treated with ethanol, the metabolic activity judged by MTT assay was inhibited in dose- and time dependent manners, but cytotoxicity was not observed. Ethanol also inhibited basal insulin secretion by 30% compared to the untreated control. However, glucose-stimulated insulin secretion was not impaired by ethanol although the basal insulin secretion was inhibited. These results imply that ethanol exert beta-cells to overwork in order to compensate inhibition of the basal secretion. This finding may at least in part explain the diabetogenic action of ethanol.
    Life Sciences 04/2002; 70(17):1989-97. · 2.56 Impact Factor